1. Field of the Invention
This invention relates generally to survey monuments and more specifically relates to an improved extraction restricting device for utilization therewith.
2. Description of the Prior Art
The prior art is exemplified by post like structures such as fence posts, fence anchors, trap anchoring stakes, ground anchors and picket pins. In most of such devices, flukes are provided to close upon the posts as it is being driven into the ground. However, if an effort is made to raise the post, a spreading out of the flukes will occur and will restrict extraction. For example, see Eddy U.S. Pat. No. 219,703, Runyon U.S. Pat. No. 362,183, Bearse U.S. Pat. No. 742,279, Rivinoja U.S. Pat. No. 1,249,200 and Lee U.S. Pat. No. 4,308,683.
In each of such prior art patents, a relatively complex construction is employed and a special construction of either the post, the devices or both is necessary.
Rousseau et al. U.S. Pat. No. 824,158 and McGreevey U.S. Pat. No. 991,525 show land anchoring means which are of general interest to illustrate the state of the art.